Floating tower frame for ocean current turbine system

Abstract

The present invention provides a floating tower frame for an ocean current turbine system comprising multiple rotors, which is designed to generate electrical power or high pressure seawater for reverse osmosis or fresh water production from steady (gyre) or tidal currents. Turbines are mounted near the base of a plurality of floating towers held in parallel between a horizontal truss structure above water and a horizontal wing at the base of the towers, below the surface. The center of gravity of the system is located in the bottom one third of the towers below the water line, while the center of buoyancy is in the top third of the towers below the surface, and the entire structure floats vertically, with respect to the towers.

I claim: 
     
       1. A marine current turbine system comprising:
 a floating frame, wherein the floating frame comprises:
 a top structural connecting member, 
 a bottom structural connecting member, and 
 a plurality of towers comprising a top end and a bottom end, wherein the top end is affixed to the top structural connecting member and the bottom end is affixed to the bottom structural connecting member; and 
 
 a plurality of turbines, wherein each turbine is located on a respective one of the plurality of towers, wherein each tower comprises an elevator to raise and lower its respective turbine relative to that tower, and 
 wherein the top structural connecting member sits above a water line, the bottom structural connecting member sits below the water line, and a center of gravity of the overall current turbine system is below its center of buoyancy. 
 
     
     
       2. The marine current turbine system of  claim 1 , wherein the bottom structural connecting member comprises a wing. 
     
     
       3. The marine current turbine system of  claim 2 , wherein the wing is fixed relative to the plurality of towers. 
     
     
       4. The marine current turbine system of  claim 2 , wherein the wing provides hydrodynamic lift to the floating frame. 
     
     
       5. The marine current turbine system of  claim 1 , wherein each tower comprises a collar for affixing a turbine to a tower. 
     
     
       6. The marine current turbine system of  claim 5 , wherein the collar can rotate about its tower. 
     
     
       7. The marine current turbine system of  claim 1 , wherein each elevator further comprises a mechanical or hydraulic drive to raise and lower each respective turbine. 
     
     
       8. The marine current turbine system of  claim 1 , further comprising one or more ballast tanks for sinking or floating a bottom end of the floating frame. 
     
     
       9. The marine current turbine system of  claim 1 , wherein the plurality of towers float on water. 
     
     
       10. The marine current turbine system of  claim 1 , wherein each of the plurality of towers are rotatable about its tower axis. 
     
     
       11. The marine current turbine system of  claim 1 , wherein each turbine comprises a torque control sensor and each respective tower comprises a yaw motor, wherein the torque control sensor detects current flow speed and activates, if the detected current flow speed is in excess of a predetermined limit, the yaw motor to reduce a respective turbine's exposure to a current flow. 
     
     
       12. The marine current turbine system of  claim 1 , wherein the plurality of towers include a first group of towers and a second group of towers, wherein the first group of towers are located in an upstream geometrical plane and the second group of towers are located in a downstream geometrical plane, the upstream geometrical plane is parallel to the downstream geometrical plane, and turbines in the upstream geometrical plane do not interfere with a current flow to turbines in the downstream geometrical plane. 
     
     
       13. The marine current turbine system of  claim 1 , further comprising a mooring line connected to each end of the floating frame to rotate the floating frame about a vertical axis. 
     
     
       14. The marine current turbine system of  claim 1 , wherein each turbine comprises variable pitch blades. 
     
     
       15. The marine current turbine system of  claim 1 , wherein one of the plurality of turbines can be shut down and serviced without affecting operation of the remaining turbines within the plurality of turbines. 
     
     
       16. A marine current turbine system comprising:
 a floating frame, wherein the floating frame comprises:
 a top structural connecting member, 
 a bottom structural connecting member, and 
 a plurality of towers affixed to the top structural connecting member and to the bottom structural connecting member; and 
 
 a plurality of turbines, wherein a turbine is located on a respective one of the plurality of towers, wherein the bottom structural connecting member comprises a wing and a pitch control for adjusting a pitch of the wing relative to the plurality of towers. 
 
     
     
       17. The marine current turbine system of  claim 16 , wherein the pitch control comprises an active control mechanism. 
     
     
       18. A marine current turbine system comprising:
 a floating frame, wherein the floating frame comprises:
 a top structural connecting member, 
 a bottom structural connecting member, and 
 a plurality of towers affixed to the top structural connecting member and to the bottom structural connecting member; and 
 
 a plurality of turbines, wherein a turbine is located on a respective one of the plurality of towers, wherein each tower comprises a collar for affixing a turbine to a tower, a track for raising and lowering the turbine relative to the structural connecting member, and a mechanical or hydraulic drive to raise and lower a turbine on its track, wherein lowering the turbines shifts a center of gravity of the system to rotate the frame from horizontal to vertical. 
 
     
     
       19. A marine current turbine system comprising:
 a floating frame, wherein the floating frame comprises:
 a structural connecting member, 
 a pitch adjustable wing, wherein the pitch adjustable wing provides hydrodynamic lift to the floating frame, and 
 a plurality of towers connecting the structural connecting member to the wing; and 
 
 a plurality of turbines, wherein a turbine is located on a respective one of the plurality of towers and the pitch adjustable wing may vary its pitch relative to the plurality of towers.